#include <iostream>
using namespace std;

int main(int argc, char *argv[])
{
	int a,b,c;
	cin>>a>>b>>c;
	bool br1,br2,br3;
	br1=(a-b)<c&&(a+b)>c;
	br2=(a-c)<b&&(a+c)>b;
	br3=(b-c)<a&&(b+c)>a;
	if(br1&&br2&&br3){
		cout<<"yes"<<endl;
	}else{
		cout<<"no"<<endl;
	}
	return 0;
}
